diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 19a58350b..16d3c0442 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/cache@v3
         with:
           path: ~/.npm
@@ -61,7 +61,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/cache@v3
         with:
           path: ~/.elm
@@ -105,7 +105,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/cache@v3
         with:
           path: ~/.npm
@@ -144,7 +144,7 @@ jobs:
       TERM: xterm
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/cache@v3
         with:
           path: ~/.elm
@@ -188,7 +188,7 @@ jobs:
     needs: [lint, elm-format, elm-test, integration]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/cache@v3
         with:
           path: ~/.elm
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index bf3337e87..52492f0be 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
         with:
           # We must fetch at least the immediate parents so that if this is
           # a pull request then we can checkout the head.
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index f44318a12..92ade8739 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/cache@v3
         with:
           path: ~/.elm